(a) Field of the Invention
The present invention relates to an engine. More particularly, the present invention relates to a continuously variable valve lift apparatus of an engine.
(b) Description of the Related Art
An internal combustion engine generates power by burning fuel in a combustion chamber in air media drawn into the chamber. Intake valves of a valve system are operated by a camshaft in order to intake the air, and the air is drawn into the combustion chamber while the intake valves are open. In addition, exhaust valves of the valve system are operated by a camshaft, and a combustion gas is exhausted from the combustion chamber while the exhaust valves are open.
An optimal operation of the intake valves and the exhaust valves depends on a rotation speed of the engine, and optimal opening/closing timing of the valves or an optimal lift depends on the rotation speed of the engine. In order to achieve such an optimal valve operation depending on the rotation speed of the engine, research has been undertaken on a continuously variable valve lift (“CVVL”) apparatus that is capable of continuously varying the valve lift depending on the engine speed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.